CN100483939C - Design of cross coupling in filter and its preparation method - Google Patents

Abstract

This invention provides the design of cross coupling in filter and method for preparing the same. Which is based on coupling relation mode and determining transmission zero number and relative position by analyzing relative phase shifting relation, according to cross coupling realizing method selecting and optimizing cross coupling parts, based on filter adjusting method determining resonance frequency distribution property, coupling parts parameter, so quick and accurate debugging resonator unit and coupling part parameters.

Description

Cross-linked design and preparation method in the filter

Technical field

The present invention relates to be used for the filter of the signal of telecommunication, specifically, relate to cross-linked design and preparation method in the narrow band filter.

Background technology

Narrow band filter is particularly useful in modern communications, especially radio communication.Along with developing rapidly of communication, frequency spectrum resource more scarcity and market competition increasingly sharpens, how in limited frequency band, to hold the multichannel communication signal simultaneously, and reduce the interference that miscellaneous equipment is caused, in the hope of effectively utilizing limited frequency resource, this is the major issue that faces in Communication System Design and the equipment development.Therefore communication system is badly in need of the high-performance narrow-band filtering device of a large amount of low costs, small size, low Insertion Loss.

Especially, some high powers, high performance filter spare are extensive use of in the base station of radio communication, and the transmission characteristic of part filtering device requires to have asymmetric rejection.Such as, the filter in duplexer or the multiplexer may require to have very high rejection in a certain side of passband, and may require very loose to the opposite side of passband.For example, the filter that is used to launch is required very high near the rejection of a side of the filter that is used to receive, with the interference that reduces to transmit by force to receiver, and its rejection away from a side of the filter that is used to receive is looser relatively.Equally, the filter that is used to receive also has similar asymmetric rejection requirement.Some other use, in order specially to protect certain or some signals of communication, also need transmission characteristic to have the filter of asymmetric rejection, to reduce cost, to reduce volume, weight reduction.

Conventional Chebyshev filter spare can not satisfy these high requests, and elliptic function filter realizes that complexity, debug difficulties and cost are higher, is difficult to extensive use.People have proposed the thought that adopts accurate elliptic function to approach, realize difficulty to reduce.It introduces limited transmission zero based on the Chebyshev filter of full limit at its passband band edge, to improve the rejection of passband band edge.Yet the analysis of this thought and implementation method are the difficult points in the design always.

Realize that accurate elliptic function filter response has two kinds of methods, a kind of is to add extra rejects trap unit, it can produce transmission zero at the passband band edge, improve the inhibition ability of passband band edge, but this method need increase extra filter cell, has therefore improved cost, has increased volume and weight.Another kind method is to introduce cross-couplings at least between a pair of non-conterminous resonator, form many transmission signals passages, the result of their stacks also may generate transmission zero at transmission passband band edge, its advantage is that it does not increase extra filter cell, can not increase cost, relatively more difficult but it is analyzed with debugging.

For second method, never have good way analysis and control cross-couplings, also easy without comparison universaling analysis method, cross-couplings modeling, realization and adjustment method in the past.For example, filter requirement according to the rules, transmission zero can't be adjusted to suitable position, and cross-couplings is too weak can not to play its inhibitory action, and it too by force again can the interference filter passband.

In the past, people had attempted utilizing non-adjacent parasitic couplings to introduce transmission zero in filtering device.Yet the general pure conduct of such effort does not have the ghost effect of control, such as the U.S. Patent No. 5 of Hey-Shipton etc., 616, description is arranged in 539, but these effort all are confined to the design of some specific filter parts, do not provide easy, universal design cheaply and implementation method.

The Chinese patent application that application number is 00806534.9, publication number is CN 1352814A discloses a kind of method of microstrip cross-coupling control apparatus, it is suitable for transmission band filter, do not provide easy general analysis, design and adjustment method, but also have following shortcoming: the ability of (1), its load power is very limited, can't satisfy the requirement (such as, radio communication base station radio-frequency (RF) front-end circuit) of specific occasion high-mechanic power capability; (2), need to adopt certain material make substrate (MgO, LaAlO3 etc.), cost is higher; (3), loss is very big, can't satisfy the requirement of the low Insertion Loss of communication equipment, though propose to adopt superconductor to reduce Insertion Loss, can cause the equipment cost increase; (4), control is very complicated, common engineers and technicians are difficult to grasp.

Application number is that 03232707.2 Chinese patent discloses the cavity body filter spare with accurate ellipse response, only is suitable for cavity body filter, does not also provide cross-linked Gneral analysis, design and implementation method.

Therefore, easy general cross-couplings analytical method, cross-couplings modeling, suitable implementation method and adjustment method thereof press in designing and developing the process of filtering device.

Summary of the invention

The purpose of this invention is to provide cross-linked design and preparation method in a kind of filter, it have general, convenient, be easy to characteristics such as common engineers and technicians' grasp.

For convenience, we at first are defined as follows used term.

Coupling channel: refer to the signal transmission path between the resonator.

Coupling unit: refer to be arranged in the parts that coupling channel is used to control coupled characteristic.

Main transmission channel: refer to the necessary transmission path of signal between the input and output resonator.

Cross-couplings transmission channel: refer to the signal additional transmissions path between the input and output resonator, comprise non-conterminous coupling channel on the path.

Transmission channel relative phase shift: the phase shift sum that refers to all resonator elements and coupling channel (parts) on the transmission path.

The equivalent admittance parameter model: coupling channel is established as four port circuit networks with one section dummy transmission line, and its dummy transmission line two ends have two admittance variators with respect to resonator element; And further being established as an equivalent admittance variator, the model that its two ends are connected with resonator element by shunt susceptance, concrete model are as shown in figure 13.

The invention provides cross-linked design and preparation method in the filter, it is characterized in that adopting following steps:

The first step is set up coupling phase relation model: if coupling channel is inductive coupled, think that it is to transmission signals phase shift-90 °; If coupling channel is capacitive coupling, think that it is to transmission signals phase shift+90 °; For resonator element, think that it is zero at the resonance point place to the transmission signals phase shift,, high-end to transmission signals phase shift-90 ° at the resonance frequency low side in resonance frequency to transmission signals phase shift+90 °; Series electrical perhaps series inductance and transmission line combination forms and has the capacitive of determining phase shift arbitrarily or inductive coupled;

Second step was judged transmission zero: the coupling phase relation model that utilizes the first step to provide obtains the criterion of following judgement transmission zero: if the relative phase shift of main transmission channel and the relative phase shift difference of cross-couplings transmission channel are 180 °, and close to the transmission signals amplitude fading, then generate transmission zero at filter transmission passband band edge; If the relative phase shift of main transmission channel is identical with the relative phase shift of cross-couplings transmission channel, then do not generate transmission zero at filter transmission passband band edge; Utilize the criterion of described judgement transmission zero to judge that the relative phase shift of the transmission channel with cross-linked filter construction form concerns, otherwise, when given transmission channel relative phase shift concerns, utilize the criterion of described judgement transmission zero to judge to have cross-linked Filter Structures form;

The design of the 3rd step has cross-linked filter: at first, set up the equivalent admittance parameter model of coupling channel; Then, according to equivalent admittance parameter model and known transmission channel relative phase shift relation, utilize the criterion of the second judgement transmission zero that provide of step, determine the parameter of cross-couplings parts, obtain having the cross-couplings Design of Filter scheme of correct transmission zero location;

The 4th step was realized the filter engineering design: the Design of Filter scheme that obtains according to the 3rd step, and the engine request of filter power bearing capacity, dimension and weight, determine the Project Realization scheme of filter;

Processing of the 5th step and debugging filter: according to the filter Project Realization scheme that the 4th step obtained, processing, assembling constitute filter; The coupling phase relation model that utilizes the first step to provide obtains the relative phase shift relation of each resonator element and each coupling and cross-couplings parts, and the cross-couplings parameters of operating part determined of the 3rd step, and debugging is met the filter that design specification requires.

Need to prove, in the filter construction of complexity, may have many barss transmission channel, the condition that still generates transmission zero not only requires the relative phase shift differential nearly 180 of two transmission channels ⁰, also require it close to the transmission signals amplitude fading, when analyzing transmission zero, only need to consider those transmission channel and cross-couplings passages by minimum resonator number.In addition, when investigating the relative phase shift difference of cross-couplings passage and main transmission channel, can not consider the phase shift of two transmission channel same sections (resonator element and coupling channel), this can simplify analysis and not influence relative phase shift poor (it specifies and sees the 8th page the 3rd section).

The capacitively coupled mode of Project Realization can be in filter: adopt semi-rigid cable, or the band lines, or little tape, or wire belt, or lumped capacitor, or the combination of discrete capacitor and above-mentioned parts thereof;

The inductive coupled mode of Project Realization can be in filter: adopt and contain the passage that loads matrix, or the little ring or the arc structure of semi-rigid cable, band line or little band formation, or the lumped inductance device, or Metallic rod, or the combination of distributed inductance device and above-mentioned parts thereof;

The present invention at first provides a kind of simple and practical cross-couplings phase model, in order to analyze the coupling phase relation.

Fig. 1 provides the coupling phase relation model between the resonator in the filter, in order to analyze the relative phase shift of each transmission channel to transmission signals.According to Circuit theory, coupling channel and resonator are established as shown in Figure 1 circuit model.Series inductance representative among Fig. 1 (1) between A, B port is inductive coupled, to transmission signals phase shift about-90 ⁰, the phase characteristic of its typical speckle parameter is seen Fig. 2; Series capacitance among Fig. 1 (2) between A, B port is represented the capacitive coupling, to transmission signals phase shift about+90 ⁰, the phase characteristic of its typical speckle parameter is seen Fig. 3; Shunt capacitance inductor loop among Fig. 1 (3) between A, B port is represented resonator element, is zero in the phase shift of resonance point place, presents approximately+90 at the resonance frequency low side ⁰Phase shift is in the high-end pact-90 that presents of resonance frequency ⁰Phase shift, the phase characteristic of its typical speckle parameter is seen Fig. 4; (the feature admittance is Y for series capacitance among Fig. 1 (4) between A, B port and transmission line _c) expression has the capacitive of determining arbitrarily phase shift or inductive coupled; (the feature admittance is Y for series inductance among Fig. 1 (5) between A, B port and transmission line _c) represent that perception or capacitive with arbitrarily definite phase shift are coupled.

Secondly, the cross-couplings phase model that utilization of the present invention proposed is analyzed several cross-linked relative phase shift relations with exemplary filter version of cross-couplings passage, determine whether to exist the feature of transmission zero and transmission zero according to the criterion of judging transmission zero, it is transmission zero number and with respect to the position of transmission passband, and analog filter performance.Several exemplary filter structures with cross-couplings passage can represent that wherein, wherein circle is represented resonator element with schematic diagram 5, and numeral wherein is the numbering of this resonator, are numbered maximum with minimum resonator element and are connected input/output port; Inductance and electric capacity are represented the coupled relation between the resonator, its possible relative phase shift of numeral on its next door.Its criterion of judging transmission zero is: close to the transmission signals amplitude fading if each the transmission channel relative phase shift that connects between the input and output resonator is opposite, the result of the destructive stack of transmission signals can generate transmission zero at transmission passband band edge so; If each transmission channel relative phase shift is identical, the result of its stack can not generate transmission zero at transmission passband band edge.Therefore, can do following analysis to the transmission zero feature of various version filters among Fig. 5.

Fig. 5 (a) expression has the cross-linked three resonator element filters of perception, and resonator 1,3 connects input/output port.At the resonance frequency low side of resonator element 2, (1 → 2 → 3 phase shifts :-90 of main transmission channel ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 3 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical (be phase shift difference be zero), so transmission zero do not occur transmitting passband low side band edge; Resonance frequency at resonator element 2 is high-end, (1 → 2 → 3 phase shifts :-90 of main transmission channel ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 3 phase shift :-90 of cross-couplings passage ⁰) between phase shift (be that phase shift difference is 180 on the contrary ⁰), the result who inversely adds produces a transmission zero at the high-end band edge of transmission passband, and filter is seen dotted line and the solid line of Fig. 6 respectively in the transmission characteristic of introducing the cross-couplings front and back.

Fig. 5 (b) expression has the cross-linked three resonator element filters of capacitive, and resonator 1,3 connects input/output port.At the resonance frequency low side of resonator element 2, (1 → 2 → 3 phase shifts :-90 of main transmission channel ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 3 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, the result who inversely adds generates a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 2 is high-end, (1 → 2 → 3 phase shifts :-90 of main transmission channel ⁰-90 ⁰-90 ⁰=-2700) with (1 → 3 phase shift :+90 of cross-couplings passage ⁰) between phase shift identical, so transmission zero can not occur at transmission passband high-end band edge, filter is seen dotted line and the solid line of Fig. 7 respectively introducing transmission characteristic before and after the cross-couplings.

Fig. 5 (c) expression has the cross-linked four resonator element filters of capacitive, and resonator 1,4 connects input/output port.Resonance frequency low side in resonator element 2 and 3, (1 → 2 → 3 → 4 phase shifts :-90 of main transmission channel ⁰+ 90 ⁰-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 4 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, the result who inversely adds generates a transmission zero at transmission passband low side band edge; Resonance frequency in resonator element 2 and 3 is high-end, (1 → 2 → 3 → 4 phase shifts :-90 of main transmission channel ⁰-90 ⁰-90 ⁰-90 ⁰-90 ⁰=-90 ⁰-360 ⁰) and (1 → 4 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, the result who inversely adds also generates a transmission zero at transmission passband high-end band edge, is introducing dotted line and the solid line that transmission spy before and after the cross-couplings sees Fig. 8 respectively.

Fig. 5 (d) expression has the cross-linked four resonator element filters of perception, and resonator 1,4 connects input/output port.Similar Fig. 5 (c) the analysis showed that, at the resonance frequency low side of resonator element 2 and 3 and high-end, main transmission channel (1 → 2 → 3 → 4) is identical with the phase shift between cross-couplings passage (1 → 4), does not generate transmission zero at transmission passband low side and high-end band edge.But imaginary frequency zero point occurs, make in its passband group delay characteristic more smooth, the dotted line of the similar Fig. 8 of its transmission characteristic, but the band outside inhibitory can variation.

Fig. 5 (e) expression has four resonator element filters of perceptual dual crossing coupling, and resonator 1,4 connects input/output port.At the resonance frequency low side of resonator element 2, transmission channel (1 → 2 → 3 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 3 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not generate transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 2 is high-end, transmission channel (1 → 2 → 3 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 3 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at the high-end band edge of transmission passband; At the resonance frequency low side of resonator element 3, transmission channel (1 → 3 → 4 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not generate transmission zero at transmission passband low side band edge; In (1 → 3 → 4 phase shifts :-90 of the high-end transmission channel of the resonance frequency of resonator element 3 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 3 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at the high-end band edge of transmission passband.Therefore, generate two transmission zeros at the high-end band edge of transmission passband, low side does not have transmission zero, sees dotted line and the solid line of Fig. 9 respectively the transmission spy who introduces the cross-couplings front and back.

Fig. 5 (f) expression has four resonator element filters of perception and the coupling of capacitive dual crossing, and resonator 1,4 connects input/output ports.At the resonance frequency low side of resonator element 2, transmission channel (1 → 2 → 3 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 3 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 2 is high-end, transmission channel (1 → 2 → 3 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 3 phase shift :+90 of cross-couplings passage ⁰) between phase shift identical, so do not produce transmission zero at transmission passband high-end band edge; At the resonance frequency low side of resonator element 3, transmission channel (1 → 3 → 4 phase shifts :+90 ⁰+ 90 ⁰-90 ⁰=+90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 3 is high-end, and (1 → 3 → 4: phase shift is+90 to transmission channel ⁰-90 ⁰-90 ⁰=-90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not generate transmission zero at transmission passband high-end band edge.Therefore, generate two transmission zeros at transmission passband low side band edge, high-end do not have a transmission zero, introducing dotted line and the solid line that transmission spy before and after the cross-couplings sees Figure 10 respectively.

Fig. 5 (g) expression has perception and capacitive three cross-linked five resonator element filters, and resonator 1,5 connects input/output port.

At the resonance frequency low side of resonator element 3, transmission channel (2 → 3 → 4 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (2 → 4 phase shifts :+90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 3 is high-end, transmission channel (2 → 3 → 4 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (2 → 4 phase shifts :+90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband high-end band edge;

At the resonance frequency low side of resonator element 2, transmission channel (1 → 2 → 4 phase shifts :-90 ⁰+ 90 ⁰+ 90 ⁰=+90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 2 is high-end, transmission channel (1 → 2 → 4 phase shifts :-90 ⁰-90 ⁰+ 90 ⁰=-90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband high-end band edge;

At the resonance frequency low side of resonator element 4, transmission channel (1 → 4 → 5 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 5 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 4 is high-end, transmission channel (1 → 4 → 5 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 5 phase shift :+90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband high-end band edge.

Therefore, generate three transmission zeros at transmission passband low side band edge, high-end do not have a transmission zero, introducing dotted line and the solid line that transmission spy before and after the cross-couplings sees Figure 11 respectively.

Fig. 5 (h) expression has the cross-linked five resonator element filters of three perception, and resonator 1,5 connects input/output port.

At the resonance frequency low side of resonator element 3, transmission channel (2 → 3 → 4 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (2 → 4 phase shifts :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 3 is high-end, transmission channel (2 → 3 → 4 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (2 → 4 phase shifts :-90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at the high-end band edge of transmission passband;

At the resonance frequency low side of resonator element 2, transmission channel (1 → 2 → 4 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 2 is high-end, transmission channel (1 → 2 → 4 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 4 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at the high-end band edge of transmission passband;

At the resonance frequency low side of resonator element 4, transmission channel (1 → 4 → 5 phase shifts :-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 5 phase shift :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 4 is high-end, transmission channel (1 → 4 → 5 phase shifts :-90 ⁰-90 ⁰-90 ⁰=-270 ⁰) and (1 → 5 phase shift :-90 of cross-couplings passage ⁰) between phase shift opposite, so generate a transmission zero at the high-end band edge of transmission passband.

Therefore, generate three transmission zeros at the high-end band edge of transmission passband, low side does not have transmission zero, sees dotted line and the solid line of Figure 12 respectively the transmission spy who introduces the cross-couplings front and back.

Need to prove, in the filter construction of complexity, may there be many barss transmission channel, but the condition that generates transmission zero not only requires two transmission channel relative phase shifts opposite, also require it close to signal amplitude decay, because the outer signal of transmission passband is subjected to violent decay during by the high quality factor resonator, its amplitude descends very fast, therefore when analyzing transmission zero, only need to consider those transmission channel and cross-couplings passages by minimum resonator number.Such as, for Fig. 5 (g) or filter construction (f), when the transmission zero contribution of investigating cross-couplings passage (1 → 5), only need to consider the relation of it and transmission channel (1 → 4 → 5), needn't consider the relation of it and transmission channel (1 → 2 → 4 → 5) and (1 → 2 → 3 → 4 → 5) etc.In addition, when investigating the relative phase shift difference of cross-couplings passage and main transmission channel, can not consider the phase place of two transmission channel same sections, this can simplify analysis and not influence relative phase shift poor.Such as, for Fig. 5 (g) or filter construction (f), when the transmission zero contribution of investigating cross-couplings passage (2 → 4), only need to consider it and the relation that differs of transmission channel (2 → 3 → 4), needn't consider the phase shift of its complete transmission passage (1 → 2 → 4 → 5) and (1 → 2 → 3 → 4 → 5).

Obvious, provide the cross-couplings phase model with the present invention and analyze the coupling of filter of various versions and cross-linked relative phase shift relation to determine the feature of transmission zero, simple and practical, be convenient to common engineers and technicians and grasp.

Once more, the present invention is based on the circuit network theory, set up the equivalent admittance parameter model of coupling channel (parts); Then, according to equivalent admittance parameter model and known transmission channel relative phase shift relation, utilize the criterion of the judgement transmission zero that second step provided, just can determine the parameter of cross-couplings parts, thus, can obtain having the cross-couplings Design of Filter scheme of correct transmission zero location;

We set up following main coupling and cross-couplings model.Optic chiasma coupling channel and control assembly are one four port network, and its equivalence is for containing dummy transmission line (characteristic admittance Y _c, electrical length θ _c) desirable admittance inverter, see Figure 13 (a).Utilize network theory, the network of Figure 13 (a) further equivalence is the network configuration of Figure 13 (b), its equivalent relation is from its corresponding abcd matrix derive out (its detailed process referring to: Nie Li Xin flat, University of Electronic Science and Technology's journal article " cross-couplings model and the realization in cavity body filter thereof ").

The final equivalent admittance transducer parameters J of coupling channel ₁₂With equivalent susceptance parameter jB ₁With jB ₂(j is an imaginary unit) is as follows:

$J_{12}=\frac{J_1{J}_2}{Y_c\sin {\mathrm{\&theta;}}_c};$ ${\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">B</figure-callout>}}_1=-\frac{{\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">J</figure-callout>}}_1^2\cot {\mathrm{\&theta;}}_c}{Y_c};$ ${\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">B</figure-callout>}}_2=-\frac{{\mathrm{<figure-callout\; id="2"\; label="J"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">J</figure-callout>}}_2^2\cot {\mathrm{\&theta;}}_c}{Y_c}$

Wherein, J ₁, J ₂It is respectively the admittance parameter that dummy transmission line connects two resonator elements.By contiguous resonator susceptance jB ₁, with jB ₂After the absorption, equivalent network is seen Figure 13 (c), the coupling between admittance inverter realization resonator 1 and 2.Among the figure, L1 and C1, L2 and C2 are respectively the equivalent LC loops of the resonator element at these coupling channel two ends.Make the susceptance Slope Parameters of its resonator be

${\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">B</figure-callout>}}_1^{\&prime;}=\frac{{\mathrm{\&omega;}}_0}{2}\frac{{\mathrm{<figure-callout\; id="2"\; label="d\; B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">d\; B</figure-callout>}}_2}{\mathrm{d\&omega;}}{|}_{\mathrm{\&omega;}={\mathrm{\&omega;}}_0};$ ${\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">B</figure-callout>}}_2^{\&prime;}=\frac{{\mathrm{\&omega;}}_0}{2}\frac{{\mathrm{<figure-callout\; id="2"\; label="d\; B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">d\; B</figure-callout>}}_2}{\mathrm{d\&omega;}}{|}_{\mathrm{\&omega;}={\mathrm{\&omega;}}_0}$

Wherein, ω is a frequency transmission signal, ω ₀It is the transmission passband central frequency.Therefore, coupling between the resonator or cross-coupling coefficient K ₁₂For

$K_{12}=\frac{J_{12}}{\sqrt{{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">B</figure-callout>}}_1^{\&prime;}{\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">B</figure-callout>}}_2^{\&prime;}}}$

Make Q1, Q2 is the exterior quality factor from the observed resonator 1,2 of equivalent transmission line, then

${\mathrm{<figure-callout\; id="1"\; label="Q"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">Q</figure-callout>}}_1=\frac{{\mathrm{<figure-callout\; id="1"\; label="Y\; c\; B"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">Y</figure-callout>}}_c{B}_{}^{}{}_1^{\&prime;}}{{\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="C200310110979E00203.png,C200310110979E00212.png"\; state="\{\{state\}\}">J</figure-callout>}}_1^2};$ ${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=\frac{{\mathrm{<figure-callout\; id="2"\; label="Y\; c\; B"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">Y</figure-callout>}}_c{B}_{}^{}{}_2^{\&prime;}}{{\mathrm{<figure-callout\; id="2"\; label="J"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">J</figure-callout>}}_2^2}$

Substitution obtains

$K_{12}=\frac{1}{\sqrt{Q_1{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="C200310110979E00202.png,C200310110979E00203.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2}\sin {\mathrm{\&theta;}}_c}$

So far, comprehensively go out the cross-coupling coefficient of following formula, promptly can determine cross coupling structure and control assembly parameter, obtain having the cross-couplings Design of Filter scheme of correct transmission zero location according to the design simulation performance of filter.

Once more, the present invention requires to determine the Project Realization scheme of filter according to filter power bearing capacity, dimension and weight etc., the general implementation method of cross-couplings parts in the filter is provided, equivalent admittance parameter model based on cross-couplings phase relation model among the present invention and coupling, by design and control cross-couplings parameters of operating part, the needed cross-coupling coefficient of implementation model in filter obtains the optimization of performance of filter.

Between two selected non-adjacent resonators, set up the cross-couplings transmission channel,, adopt semi-rigid cable for the capacitive cross-couplings, the band lines, little tape, other wire, lumped capacitor, discrete capacitor and their combiner are realized.Typical implementation in cavity body filter is seen Figure 14, and number in the figure 1 is the input/output port of filter, the 2nd, and semi-rigid cable is used as capacitive cross-couplings parts.

For perceptual cross-couplings, adopt and contain the passage that loads matrix, little ring or arc structure that semi-rigid cable, band line or little band constitute, Metallic rod, the lumped inductance device, the distributed inductance device, lumped capacitor, and their combiner is realized.Typical implementation in cavity body filter is seen Figure 15, and number in the figure 1 is the input/output port of filter, the 3rd, and the metal semi-ring is as perceptual cross-couplings parts.

The general implementation of cross-couplings parts in filter seen signal Figure 16 and 17, and circle is represented non-adjacent resonator element among the figure.Figure 16 provides and adopts single cross-couplings parts to form cross-linked scheme schematic diagram in several filters.The parallel component that Figure 16 (1) expression is connected with resonator forms the capacitive cross-couplings; The parallel component that extra distributed capacitance is contained at the middle part that Figure 16 (2) expression is connected with resonator forms the capacitive cross-couplings; The coupling unit that Figure 16 Figure 16 (3) expression is not connected with resonator forms the capacitive cross-couplings; Figure 16 (4) expression is not connected with resonator and the middle part is contained the coupling unit of extra distributed capacitance and formed the capacitive cross-couplings; Figure 16 (5) provides and is not connected with resonator and the middle part is contained the coupling unit of extra distributed inductance and formed capacitive or perceptual cross-couplings; Figure 16 (6) provides and is connected with resonator and the middle part is contained the coupling unit of extra distributed inductance and formed capacitive or perceptual cross-couplings; Figure 16 (7) expression is connected with resonator and the coupling unit formation capacitive cross-couplings of extra lumped capacity is contained at the middle part; Figure 16 (8) provides and is connected with resonator and the middle part is contained the coupling unit of lumped inductance and formed perceptual cross-couplings; Figure 16 (9) expression is not connected with resonator and the middle part is contained the coupling unit of extra lumped capacity and formed the capacitive cross-couplings; Figure 16 (10) provides and is not connected with resonator and the middle part is contained the coupling unit of lumped inductance and formed perceptual cross-couplings.

Figure 17 adopts combination cross-couplings parts to form cross-linked schematic diagram in the filter, only provided the situation of two combiners among the figure, but can comprise a plurality of combiners.Therefore, should not be construed as and only comprise the figure restriction that provides among Figure 17.Figure 17 (1) expression is not connected with resonator and contains the cross-couplings parts formation capacitive in parallel or the perceptual cross-couplings of lump or discrete capacitor and inductor; Figure 17 (2) expression is connected with resonator and contains the cross-couplings parts formation capacitive in parallel or the perceptual cross-couplings of lump or discrete capacitor and inductor; Figure 17 (3) expression is not connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings of lumped capacitor and distributed inductance device; Figure 17 (4) expression is connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings of lumped capacitor and distributed inductance device; Figure 17 (5) expression is not connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings of discrete capacitor and distributed inductance device; Figure 17 (6) expression is connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings of discrete capacitor and distributed inductance device.

At last, the invention provides adjustment method with cross-linked filter.According to filter Project Realization scheme, processing, assembling constitutes filter, version and coupling and cross-couplings parts according to the designing institute employing, utilize each resonator element that the coupling phase relation model that provides among the present invention obtains and the relative phase shift relation of each coupling unit, determine the resonance frequency distribution of each resonator and the basic parameter of each resonator element thereof, and utilize the coupling that the equivalent admittance parameter model determines and the basic parameter of cross-couplings parts, the parameter of fine setting resonator element and coupling unit can be debugged rapidly and accurately and is met the filter that design specification requires.

The present invention has following beneficial effect:

1. have cross-linked filter and can realize the transmission response of asymmetric rejection.

2. the cross-couplings design that provides is general and easy with implementation method, is suitable for filters such as little band, cavity, is easy to realize.

3. compare with common Chebyshev filter, the resonator element decreased number; Compare with elliptic function filter, simple for structure, debug easy.

4. have cross-linked filter and have low Insertion Loss, high quality factor and high selectivity; Reduced the filtering device cost, reduced volume, alleviated weight, can satisfy the demand of modern communications high performance filter spare.

5. the filter cross-couplings analytical method that provides can be used for analyzing the coupling and the cross-linked relative phase shift relation of the filter of various versions, thereby determines the feature of transmission zero.

6. the filter cross-couplings analytical method that provides helps to analyze, designs and the debugging filter.

7. the filter cross-couplings universaling analysis method that provides, simple and practical, common engineers and technicians are easy to grasp.

8. the coupling of the filter that provides and cross-linked universal model, the parameter with the cross-couplings parts of can determining to be coupled, thus in filter, realize needed coupling and cross-coupling coefficient, suitable transmission zero location is set.

9. the cross-linked general implementation method of the filter that provides can realize the cross-coupling coefficient of appointment by selecting, design and control cross-couplings parts in filter.

10. in the cross-linked general implementation of the filter that provides, the cross-coupling control parts have bigger electric size, and manufacturing materials does not have specific (special) requirements, are convenient to make and field adjustable, are convenient to filtering device and produce in batches.

11. the cross-linked general implementation method of the filter that provides has bigger flexibility, method is easy, and is workable, and common engineers and technicians are easy to grasp and design.

12. the filter adjustment method that provides can be debugged filter rapidly and accurately, common engineers and technicians can grasp.

Description of drawings

Fig. 1 is a coupling phase relation model schematic diagram.

Wherein, figure (1) expression is inductive coupled; The coupling of figure (2) expression capacitive; Figure (3) expression resonator element; Figure (4) is that series capacitance and transmission line combination form capacitive or inductive coupled; Figure (5) is that series inductance and transmission line combination form capacitive or inductive coupled.Among the figure, A, B represent the circuit network port.

Fig. 2 is inductive coupled typical speckle parameter phase characteristic curve.

Fig. 3 is capacitively coupled typical speckle parameter phase characteristic curve.

Fig. 4 is the typical speckle parameter phase characteristic curve of resonator element.

Fig. 5 is the exemplary filter structural representation with cross-couplings passage.

Wherein, figure (a) has the cross-linked three resonator element filter schematic of perception;

Figure (b) has the cross-linked three resonator element filter schematic of capacitive;

Figure (c) has the cross-linked four resonator element filter schematic of capacitive;

Figure (d) has the cross-linked four resonator element filter schematic of perception;

Figure (e) is four resonator element filter schematic with perceptual dual crossing coupling;

Figure (f) is four resonator element filter schematic with perception and the coupling of capacitive dual crossing;

Figure (g) has perception and capacitive three cross-linked five resonator element filter schematic;

Figure (h) has the cross-linked five resonator element filter schematic of three perception.

Among the figure, circle is represented resonator element, and numeral wherein is the numbering of this resonator, is numbered maximum with minimum resonator and is connected input/output port; Inductance and electric capacity are represented the coupled relation between the resonator, its possible relative phase shift of numeral on its next door.

Fig. 6 provides has the cross-linked three resonator element filters of perception in the transmission characteristic of introducing before and after the cross-couplings shown in Fig. 5 (a).

Fig. 7 provides has the cross-linked three resonator element filters of capacitive in the transmission characteristic of introducing before and after the cross-couplings shown in Fig. 5 (b).

Fig. 8 provides has the cross-linked four resonator element filters of capacitive in the transmission characteristic of introducing before and after the cross-couplings shown in Fig. 5 (c).

Fig. 9 provides the four resonator element filters with perceptual dual crossing coupling shown in Fig. 5 (e) in the transmission characteristic of introducing the cross-couplings front and back.

Figure 10 provides the four resonator element filters with perception and the coupling of capacitive dual crossing shown in Fig. 5 (f) in the transmission characteristic of introducing the cross-couplings front and back.

Figure 11 provides has perception and capacitive three cross-linked five resonator element filters in the transmission characteristic of introducing before and after the cross-couplings shown in Fig. 5 (g).

Figure 12 provides has the cross-linked five resonator element filters of three perception in the transmission characteristic of introducing before and after the cross-couplings shown in Fig. 5 (h).

Figure 13 is the equivalent admittance parameter model schematic diagram of coupling channel (parts).

Wherein, figure (a) provides the admittance inverter illustraton of model with dummy transmission line;

Figure (b) is the equivalent network structural representation of Figure 13 (a);

Figure (c) is main coupling and cross-linked final equivalent admittance converter model.

Among the figure, Y _cBe the characteristic admittance of dummy transmission line, its electrical length is θ _c, J ₁, J ₂Be respectively the admittance parameter that dummy transmission line connects two resonator elements, J ₁₂, jB ₁With jB ₂Be the final equivalent admittance transducer parameters and the equivalent susceptance parameter (j is an imaginary unit) of coupling channel, L1 and C1, L2 and C2 are respectively the equivalent LC loops of the resonator element at these coupling channel two ends.

Figure 14 provides a kind of cross-linked cavity body filter schematic diagram of capacitive that has.Among the figure, label 1 is represented input/output port, and label 2 is that semi-rigid cable is used as capacitive cross-couplings parts.

Figure 15 provides a kind of perceptual cross-linked cavity body filter schematic diagram that has.Among the figure, label 1 is represented input/output port, and label 3 is that the metal semi-ring is as perceptual cross-couplings parts.

Figure 16 adopts single cross-couplings parts to form cross-linked schematic diagram in the filter.

Wherein, figure (1) represents that the parallel component that is connected with resonator forms capacitive cross-couplings schematic diagram;

The parallel component that extra distributed capacitance is contained at the middle part that figure (2) expression is connected with resonator forms capacitive cross-couplings schematic diagram;

The coupling unit that figure (3) expression is not connected with resonator forms capacitive cross-couplings schematic diagram;

Figure (4) expression is not connected with resonator and the middle part is contained the coupling unit of extra distributed capacitance and formed capacitive cross-couplings schematic diagram;

Figure (5) provides and is not connected with resonator and the middle part is contained the coupling unit of extra distributed inductance and formed capacitive or perceptual cross-couplings schematic diagram;

Figure (6) provides and is connected with resonator and the middle part is contained the coupling unit of extra distributed inductance and formed capacitive or perceptual cross-couplings schematic diagram;

Figure (7) expression is connected with resonator and the coupling unit formation capacitive cross-couplings schematic diagram of extra lumped capacity is contained at the middle part;

Figure (8) provides and is connected with resonator and the middle part is contained the coupling unit of lumped inductance and formed perceptual cross-couplings schematic diagram;

Figure (9) expression is not connected with resonator and the middle part is contained the coupling unit of extra lumped capacity and formed capacitive cross-couplings schematic diagram;

Figure (10) provides and is not connected with resonator and the middle part is contained the coupling unit of lumped inductance and formed perceptual cross-couplings schematic diagram.

Among the figure, circle is represented non-adjacent resonator element.

Figure 17 adopts two combination cross-couplings parts to form cross-linked schematic diagram in the filter.

Wherein, figure (1) expression is not connected with resonator and contains the cross-couplings parts formation capacitive in parallel or the perceptual cross-couplings schematic diagram of lump or discrete capacitor and inductor;

Figure (2) expression is connected with resonator and contains the cross-couplings parts formation capacitive in parallel or the perceptual cross-couplings schematic diagram of lump or discrete capacitor and inductor;

Figure (3) expression is not connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings schematic diagram of lumped capacitor and distributed inductance device;

Figure (4) expression is connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings schematic diagram of lumped capacitor and distributed inductance device;

Figure (5) expression is not connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings schematic diagram of discrete capacitor and distributed inductance device;

Figure (6) expression is connected with resonator and contains connect the cross-couplings parts formation capacitive or the perceptual cross-couplings schematic diagram of discrete capacitor and distributed inductance device.

Among the figure, circle is represented non-adjacent resonator element.

Figure 18 is the ends of the earth resonant cavity filter structural representation with four transmission zeros of symmetry.

Figure 19 provides the test curve of the filter of structure shown in Figure 180.

Figure 20 is illustrated in high-end band edge and contains two transmission zeros, contains ten utmost point resonator filter structural representations of the asymmetric transmission response of a transmission zero at low side.

Figure 21 provides the test curve of the filter of structure shown in Figure 20.

Figure 22 is the mock-up figure with cross-linked four coaxial resonant cavity filters.

Figure 23 provides the transmission response test curve of the filter of structure shown in Figure 22.

Embodiment

Embodiment 1:

Ends of the earth resonant cavity filter, its structural representation is seen Figure 18, it is that Fig. 5 (e) merges the structure that forms with Fig. 5 (f).Known by preceding surface analysis, Fig. 5 (e) expression has four resonator element filters of perceptual dual crossing coupling, contains two transmission zeros at the high-end band edge of transmission passband, and low side does not have transmission zero, the special solid line of seeing Fig. 9 of its transmission; Fig. 5 (f) expression has four resonator element filters of perception and the coupling of capacitive dual crossing, contain two transmission zeros at transmission passband low side band edge, high-end do not have a transmission zero, its transmission characteristic is seen the solid line of Figure 10, therefore, the filter transmission characteristic of Figure 18 version contains four transmission zeros, and wherein two transmission zeros being produced of resonator 1～4 are positioned at passband low side band edge, and two transmission zeros that resonator 5～8 is produced are positioned at the high-end band edge of passband.This filter characteristic test result is seen Figure 19, comes to the same thing with the cross-couplings phase analysis model analysis that utilizes the present invention to provide.Present embodiment shows, the coupling of the filter of the cross-couplings phase analysis model analysis labyrinth form that application the present invention provides and cross-linked relative phase relation, determining whether to exist the feature of transmission zero and transmission zero, is a kind of simple and practical method for filter analysis, design and debugging.

Embodiment 2:

Ten utmost point resonator filters, its structural representation is seen Figure 20, and resonator 1 is connected input/output port with 10, and the master between its resonator is coupled as the capacitive coupling.Its transmission zero characteristic of cross-couplings phase analysis model analysis of utilizing the present invention to provide is as follows.

At the resonance frequency low side of resonator element 3, transmission channel (2 → 3 → 4 phase shifts :+90 ⁰+ 90 ⁰+ 90 ⁰=+270 ⁰) and (2 → 4 phase shifts :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 3 is high-end, transmission channel (2 → 3 → 4 phase shifts :+90 ⁰-90 ⁰+ 90 ⁰=+90 ⁰) and (2 → 4 phase shifts :-90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at the high-end band edge of transmission passband.

At the resonance frequency low side of resonator element 5, transmission channel (4 → 5 → 6 phase shifts :+90 ⁰+ 90 ⁰+ 90 ⁰=+270 ⁰) and (4 → 6 phase shifts :+90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 5 is high-end, transmission channel (4 → 5 → 6 phase shifts :+90 ⁰-90 ⁰+ 90 ⁰=+90 ⁰) and (4 → 6 phase shifts :+90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband high-end band edge.

At the resonance frequency low side of resonator element 8, transmission channel (7 → 8 → 9 phase shifts :+90 ⁰+ 90 ⁰+ 90 ⁰=+270 ⁰) and (7 → 9 phase shifts :-90 of cross-couplings passage ⁰) between phase shift identical, so do not have transmission zero at transmission passband low side band edge; Resonance frequency at resonator element 8 is high-end, transmission channel (7 → 8 → 9 phase shifts :+90 ⁰-90 ⁰+ 90 ⁰=+90 ⁰) and (7 → 9 phase shifts :-90 of cross-couplings passage ⁰) between phase shift opposite, so produce a transmission zero at the high-end band edge of transmission passband.

The phase shift of other resonator does not have influence to the filter transmission zero.Therefore, generate two transmission zeros at the high-end band edge of transmission passband, a transmission zero appears in low side.

This filter characteristic test result is seen Figure 21, coincide with the cross-couplings phase analysis model analysis result who utilizes the present invention to provide.Present embodiment shows, the coupling of the filter of the various versions of cross-couplings phase analysis model analysis that application the present invention provides and cross-linked relative phase relation, the transmission zero feature of determining the filter transmission characteristic exactly be can make things convenient for, analysis, design and the debugging of high performance filter are of value to.

Embodiment 3:

Designed the coaxial resonant cavity filter that aluminium alloy is made, mock-up is seen Figure 22.Four coaxial resonant cavities have been left in the aluminium alloy box, the input/output device that is connected with coaxial resonant cavity (I/O and O/I) is a coaxial probe, in each coaxial resonant cavity, installed tuning screw additional, the main signal channel between coaxial resonant cavity, between the head and the tail coaxial resonant cavity, left a rectangle auxiliary signal passage, laid quarter-wave rectangular band line in this rectangular channel as cross-coupling control parts (1).

The coupling phase relation model of this filter is seen Fig. 5 (c), and it is to have the cross-linked four resonator element filters of capacitive.The coupling and the cross-linked relative phase of the filter of this version of cross-couplings phase analysis model analysis that application the present invention provides concern as can be known the resonance frequency low side in resonator element 2 and 3, (1 → 2 → 3 → 4 phase shifts :-90 of main transmission channel ⁰+ 90 ⁰-90 ⁰+ 90 ⁰-90 ⁰=-90 ⁰) and (1 → 4 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, the result who inversely adds generates a transmission zero at transmission passband low side band edge; Resonance frequency in resonator element 2 and 3 is high-end, (1 → 2 → 3 → 4 phase shifts :-90 of main transmission channel ⁰-90 ⁰-90 ⁰-90 ⁰-90 ⁰=-90 ⁰-360 ⁰) and (1 → 4 phase shift :+90 of cross-couplings passage ⁰) between phase shift opposite, the result who inversely adds also generates a transmission zero at transmission passband high-end band edge, and therefore a transmission zero is arranged in the passband both sides.The solid line of its analogue transmission performance plot 8.

The transmission characteristic of its test is seen Figure 23.As remove the cross-coupling control parts and seal the auxiliary signal passage, then this filter has just become conventional Chebyshev filter, and the dotted line of its transmission characteristic and Fig. 8 coincide.If changing cross-couplings band line is 1/5th wavelength, and records transmission zero behind the corresponding adjustment tuning screw and outwards move relative to the passband center.This embodiment shows that the cavity body filter of this kind structure has been introduced a pair of limited transmission zero at the passband band edge, has improved the rejection of passband band edge effectively.The longthening belt line has then strengthened cross-couplings, intracardiac moving in the relative passband of the transmission zero of band edge, and the near-end rejection has improved; The opposite band line that shortens has weakened cross-couplings, and the relative passband of the transmission zero of band edge moves outside the center, and the inhibition of far-end improves.Remove cross-couplings, then do not have limited transmission zero.Cross-couplings phase analysis model provided by the invention is the transmission zero feature of analysis filter transmission characteristic accurately.Filter master provided by the invention is coupled and the cross-couplings universal model, can be used for determining the parameter of coupling and cross-couplings parts, and correct transmission zero location is set, and obtains high performance filter.Cross-couplings implementation method provided by the present invention, simple and effective.

Claims (3)

1, cross-linked design and preparation method in a kind of filter is characterized in that adopting following steps:

The first step is set up coupling phase relation model: if coupling channel is inductive coupled, think that it is to transmission signals phase shift-90 °; If coupling channel is capacitive coupling, think that it is to transmission signals phase shift+90 °; For resonator element, think that it is zero at the resonance point place to the transmission signals phase shift,, high-end to transmission signals phase shift-90 ° at the resonance frequency low side in resonance frequency to transmission signals phase shift+90 °; Series electrical perhaps series inductance and transmission line combination forms and has the capacitive of determining phase shift arbitrarily or inductive coupled; Described coupling channel is meant the signal transmission path between the resonator;

Second step was judged transmission zero: the coupling phase relation model that utilizes the first step to provide obtains the criterion of following judgement transmission zero: if the relative phase shift of main transmission channel and the relative phase shift difference of cross-couplings transmission channel are 180 °, and close to the transmission signals amplitude fading, then generate transmission zero at filter transmission passband band edge; If the relative phase shift of main transmission channel is identical with the relative phase shift of cross-couplings transmission channel, then do not generate transmission zero at filter transmission passband band edge; Utilize the criterion of described judgement transmission zero to judge that the relative phase shift of the transmission channel with cross-linked filter construction form concerns, otherwise, when given transmission channel relative phase shift concerns, utilize the criterion of described judgement transmission zero to judge to have cross-linked Filter Structures form; Described main transmission channel is meant the necessary transmission path of the signal between the input and output resonator; Described cross-couplings transmission channel is meant the signal additional transmissions path between the input and output resonator, comprises non-conterminous coupling channel on the path; Described cross-couplings is meant the coupling except that the coupling of main transmission channel between the input and output resonator;

The design of the 3rd step has cross-linked filter: at first, set up the equivalent admittance parameter model of coupling channel; Then, according to equivalent admittance parameter model and known transmission channel relative phase shift relation, utilize the criterion of the second judgement transmission zero that provide of step, determine the parameter of cross-couplings parts, obtain having the cross-couplings Design of Filter scheme of correct transmission zero location; Described equivalent admittance parameter model is meant coupling channel is established as four port circuit networks with one section dummy transmission line, its dummy transmission line two ends have two admittance variators with respect to resonator element, and further be established as an equivalent admittance variator, the model that its two ends are connected with resonator element by shunt susceptance;

The 4th step was realized the filter engineering design: the Design of Filter scheme that obtains according to the 3rd step, and the engine request of filter power bearing capacity, dimension and weight, determine the Project Realization scheme of filter;

Processing of the 5th step and debugging filter: according to the filter Project Realization scheme that the 4th step obtained, processing, assembling constitute filter; The coupling phase relation model that utilizes the first step to provide obtains the relative phase shift relation of each resonator element and each coupling and cross-couplings parts, and the cross-couplings parameters of operating part determined of the 3rd step, and debugging is met the filter that design specification requires.

2, cross-linked design and preparation method in a kind of filter according to claim 1, it is characterized in that described capacitively coupled Project Realization mode is: semi-rigid cable, or band lines, or little tape, or wire belt, or lumped capacitor, or the combination of discrete capacitor and above-mentioned parts thereof.

3, cross-linked design and preparation method in a kind of filter according to claim 1, it is characterized in that described inductive coupled Project Realization mode is: contain the passage that loads matrix, or the little ring or the arc structure of semi-rigid cable, band line or little band formation, or lumped inductance device, or Metallic rod, or the combination of distributed inductance device and above-mentioned parts thereof.

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